The operating system of a computer server is an interface between the hardware and the software applications of the computer system. Each operating system, sometimes referred to as a kernel, typically includes an element of software code known as a device driver. The term kernel is sometimes used to refer to the lowest level of the operating system. The device driver of the kernel typically resides in the lowest level of the operating system and provides the low level interface between the hardware elements of the computer system and the operating system to direct the operation of the hardware elements of the computer system.
Because the device driver of an operating system provides an interface between the hardware of the computer system and the application programs of the computer systems, the application programs of the computer system are able to interface with the hardware without the necessity of making functions calls that are specific to the hardware architecture of each model of computer system. Through function calls to the operating system or kernel application programs may request certain action by the hardware resources of the computer system, including such hardware resources as the CPU, storage devices, memory, and input/output devices. Once such a function call is received by the operating system, the device driver of the operating system or kernel interfaces with the hardware resources of the computer system. A device driver, which serves as a software interface between the application and the hardware architecture of the computer system, may be written specifically for the hardware architecture of the computer system. The operating system communicates with the device driver of the computer system to request certain functions of the hardware of the computer system, including CPU scheduling functions, interrupt functions, memory management functions, memory storage and retrieval functions, and device input and output functions.
Open source operating systems, such as Linux, a standardized version of which is marketed by Red Hat, Inc. of Durham, N.C., have come into more common use in computer systems. Open source software is characterized by freely available source code. In the case of an open source operating system, the source code of the operating system is accessible to users of the operating system. Because the source code of an open source operating system is available, the software may be readily modified to accommodate the needs or desires of the user. Even the most sensitive portions of an open source operating system, including the kernel, may be modified. After a modification by the user, the user may choose to distribute the source code to others, leading to a gradual evolution in the product. It is theorized that the ability to modify and distribute open source software leads to the faster correction of bugs and improvement of the functionality of the software, as compared with proprietary software packages. The source code for the Red Hat Linux operating system may be downloaded from the Internet or the software may be purchased from a vendor in a packaged format.
With respect to the Linux open source operating system, the Linux operating system runs on a number of hardware platforms, including computer systems platforms for desktop computer systems and server systems. A number of vendors package and sell a standardized version of the Linux operating system. This packaged system includes application programs, installation tools, utility programs, development tools, graphical interface, and the device drivers. Even though a standardized version of an open source operating system may be purchased from a third party vendor, the operating system, including the kernel, may be readily modified by the user to create a customized operating system.
Computer system manufacturers are now offering the option of installing open source operating systems in computers systems, including server systems. As part of the open source operating system, the computer system manufacturer will typically include in the operating system package a device driver that is specific to the computer system model or family of computer system models of the computer system manufacturer. One difficulty of providing an open source driver as part of an open source operating system is that the source code of the open source driver may contain proprietary information concerning the hardware architecture of the computer system or the family of computer systems of the computer system manufacturer. A possible solution to this problem is to provide to users a precompiled device driver. The user or a competitor would not be able to identify in the compiled device driver the proprietary information that could possibly be found in the source code of the device driver.
The option of providing a precompiled device driver is not completely satisfactory. In the Linux operating system, for example, the precompiled device driver only works with the kernel that the driver is compiled against. When the device driver is compiled for the sake of execution, the device driver will expect to receive function calls from the kernel that are named according to a naming convention in which the suffix of the function call name is specific to the Linux kernel. A change to the source code of the kernel, which would necessitate the recompilation of the kernel, results in a change to the names of the function calls of the kernel. In this instance, the names of the function calls of the kernel would not match the names expected by the compiled device driver. As a result, a device driver only works for the kernel that the device driver is compiled against because the function call names must match between the compiled kernel and the compiled device driver.
Although a hardware vendor can supply precompiled device drivers to support a few popular Linux kernels, many other kernels will be left unsupported. If a computer manufacturer, wants its device driver to support all Linux kernels, source code for the device driver must be provided to vendors of standardized version of the open source operating system so the source code can be distributed to customers, enabling the customers to compile the device driver against the kernel of the customer's operating system. The difficulty with the approach of distributing an open source driver is that if proprietary information concerning the products of the hardware manufacturer is included in the open source driver, this information may become known to others.